Initial stage wireless communication systems have been developed to provide a voice service while securing activity of a user. However, the wireless communication system gradually extends an area from a voice service to a data service. At present, the wireless communication system has been developed to provide a high-speed data service.
The wireless communication system may include a radio access network (RAN). Components of a radio access network that interacts with a terminal may communicate with a terminal via an air interface. The remaining components of the wireless communication system may be mostly connected to the terminal in a wired manner.
A radio access network component that interacts with the terminal via the air interface may include some of, for example, an evolved Node B (eNB), a node B (NB), or a radio network subsystem (RNS) including the same, a base transceiver station (BTS) or a base station subsystem (BSS) including the same, a radio access point, a home eNB, a home NB, a home eNB gateway (GW), and X2 GW. In the present specification, for convenience, the term base station will be used to refer to at least one of the examples of the radio access network components listed above or the radio access network itself.
A base station may be configured of one or more cells. A cell governs a specific range, and the terminal is serviced within a range of cells. Here, the cell means a cell of a cellular system, and the base station means a device for managing and controlling the cell. However, in the present specification, for convenience, the cell and the base station may be used as the same meaning. For example, even in describing the embodiment, the cell and the base station may be interchanged with each other for convenience.
Since the base station provides services to the terminal via the air interface, each base station has adequate coverage to provide the service.